I'm with ATM on this one Twee - The treatment and first few hundred miles of an engines life is critical to it's future condition and performance, reliability and longevity.
For the minor costs of replacing oil and filter at 500 miles it is a small and cheap price to pay and a sensible precaution to ensure that you have drained out all the tiny particles of "crud" and metal granules created by increased initial wear in the initial stages of bedding in the components, by draining off the old contaminated factory oil and replacing with new clean correct quality oil of the type as recommended by the manufacturer.
I believe that ATM's trike is actually a recycled teenagers Tuk-Tuk with a supercharged Golf VR6 engine, with him hanging on for dear life whilst he spends all night blazing the streets & terrorising the local citizens, in between frequenting gambling and drinking establishments, amongst his visits to other more shady places of ill-repute......or so word has it with the boys down at the Winchester club.!
: -- )